The members of the Climate Change Authority, which include its chair Grant King, hold prominent roles in companies who profit from the carbon offset industry.

Former members of the authority, which has since been given a more prominent role in achieving the country's emissions reduction target following the Labor government's election, have questioned whether the members should remain in the role.

Around three-quarters of Australians want the federal authority chaired by a climate scientist and for members not to be employed by companies impacted by its recommendations and advice, polling by progressive think tank The Australia Institute has revealed.

Institute researcher Polly Hemming said the climate authority's three most recent reports, including one released Monday, have all advocated for expanding carbon offsets instead of more drastic decarbonisation methods, making it a "one-trick pony".

But the climate authority's chief executive insists its member conflicts of interests are appropriately managed.

Mr King, a former chief executive of gas giant Origin Energy, sits on the board of Australia's largest carbon credits aggregator, GreenCollar.

Meanwhile Mark Lewis, a member of the authority, is a director of a number of carbon trading firms, including Australian Integrated Carbon.

Susie Smith is the chief executive of fossil fuel industry lobby group, Australian Industry Greenhouse Network.

Mr King, Mr Lewis and Ms Smith all declared and discussed potential conflicts as published in a management plan relating to the authority's review of international offsets in May this year.

Sam Mostyn also serves as a senior advisor for Pollination, an investment and advisory firm trading in carbon credits.

Her conflicts were not included in the May document, having joined the board in September.

"The authority conducts its work in an open and transparent manner, including in relation to public consultation and probity matters," chief executive Brad Archer said in a statement to The Canberra Times.

"Members are excluded from providing advice or recommendations when it relates to decisions that they could benefit from in their outside work.

"Should a member have conflict of interest in relation to a matter which the authority is advising the government on, the remaining members may decide to exclude the member from the discussion entirely, or the member may be allowed to participate in a discussion on the matter but not in the decision about the authority's advice.

"The authority's analysis and recommendations are always published, so people are free to assess and form their own view on the merits of the authority's work."

The Canberra Times is not suggesting the members have undertaken any wrongdoing.

Australian National University Professor Andrew Macintosh, who was a member of the authority in 2015, said the conflicts raised questions over the advice it delivered to government.

"When you're meant to be providing a trusted provision of policy advice, it's really important that you don't have those conflicts," Professor Macintosh said.

"It can distort people's views and directly bias the policy advice you're providing, but it also creates this perception of bias.

"I think the role of people who are directly employed by industry, particularly lobbyists for industry, I just don't think that it's tenable for those people to hold positions as members of the Climate Change Authority."

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Another former member, climate scientist Professor David Karoly, who was a member between 2012 and 2017, said while policies and registers of interest were in place to mitigate conflicts, the risks weren't entirely removed.

"Their existence, as members of the Climate Change Authority, even if they remove themselves from active discussions, may well still lead to their involvement in off-the-record or private conversations in tea times or lunch breaks of meetings," he said.

"Even their presence as members of the Climate Change Authority will affect and influence potentially some of the staff and their decisions and their recommendations."

Climate Change Minister Chris Bowen announced the climate authority's membership would expand to nine members from six in September, promising to make it "better placed to oversee emissions reduction efforts and provide government with expert advice".

The authority was also allocated $47.1 million over the next four years under the federal budget as part of its expanded advisory role.

But Ms Hemming said the authority's three latest publications showed climate policy advice did not reflect the scientific need for rapid decarbonisation.

"The science and economics is clear - we need to avoid and reduce emissions now and offset whatever remains later.

"The CCA seems uninterested in phasing out fossil fuels, increasing energy efficiency or economy-wide carbon pricing."